THOUSANDS of workers are being employed by councils, universities and public bodies in Scotland on controversial "zero-hours" contracts.

The contracts - which leave staff with no guarantee of any work - have come under intense scrutiny through their use by private firms such as SportsDirect and Cineworld. It has also emerged that Buckingham Palace and the UK Government have workers employed on such terms.

An investigation by the Sunday Herald has found 11 out of Scotland's 32 councils employ at least 7000 workers on some form of zero-hours contract.

Four universities - including Edinburgh, Glasgow, Dundee and Edinburgh Napier - also have just over 4700 staff on contracts with no guarantee of hours.

National Galleries Scotland and National Museums Scotland have nearly 20 zero-hours staff and the Scottish Parliament's catering contractor has eight.

Police Scotland said the former Grampian force had engaged four relief administration assistants on zero-hours contracts last year and the former Central Scotland force has 15 relief cleaners on such contracts in the past five years.

Organisations which offer the contracts claim they give flexibility to both employer and employee when work is irregular and hours variable.

But critics say the contracts -which mean an employer pays staff only if they are needed and is not obliged to offer holiday or sick pay - stretch "almost to breaking point" the concept of employment.

Drew Morrice, assistant secretary of the Educational Institute of Scotland (EIS) union, which represents teachers and university lecturers, said: "We certainly do have a concern about the use of zero-hours contract.

"The problem is it basically allows the employer to turn on and off the tap of work and it is very hard for an individual to have any comeback.

"I'm struggling to see a benefit [for the employee] in something which allows your employer to say basically at the drop of a hat there is no work for you, we will be back in touch when work is available."

Edinburgh University said it has 3832 staff on "hours to be notified" (HTBN) contracts. The majority - nearly 3000 - are tutors, demonstrators or support staff, but others work in areas such as catering, events and library services.

A university spokeswoman said no more than 5% of the work at the university is paid this way.

She added: "HTBN contracts offer flexible employment, while providing the same terms, conditions and benefits other employees receive."

Glasgow University had 734 staff on zero-hours contracts as of April this year, ranging from lecturers to catering assistants and student counsellors.

A university spokesman said in most cases work was agreed over a period of time and employees were under no obligation to accept work.

Dundee University said a "small number" of zero-hours staff provide exercise classes at its Sports Institute. A spokesman added: "We do not use any zero-hours contracts across our academic and research activity."

Figures collated by the EIS also show 185 lecturers, 30% of the total, were employed by Edinburgh Napier University on zero-hours contracts in 2012.

A spokeswoman for Napier said fewer than 5% of teaching hours were delivered by staff on such contracts. She added that zero-hours staff are on permanent contracts, with associated benefits.

Local authorities also use the contracts for a variety of roles.Clackmannanshire Council said it engaged 452 relief staff on a "supply as required basis" to cover sickness and holidays, mostly in facilities management.

Argyll and Bute confirmed it employs 126 zero-hours staff, mainly in care, while Midlothian has 335 zero-hours contractors including a casual accountant, youth workers, supply teachers and a sports instructor.

Moray Council said it had employed 966 people, including caretakers, nursery nurses and leisure attendants, on zero-hours or "relief" contracts as of June of this year.

East Dunbartonshire revealed it had 32 music tutors on zero-hours contracts out of a total of 4362 staff.

Scottish Borders Council said it had 47 home care staff under such an arrangement, but it no longer issues zero-hours contracts.

Falkirk Council confirmed it used zero-hours contracts, mostly for home care staff, while Highland Council said such contracts had been issued for jobs including care worker, social worker and driver. Neither council gave figures.

Aberdeenshire Council said it had 3919 staff on "relief" or "supply" contracts out of 17,982, including teachers and care workers. Like some employers, Aberdeenshire Council offers such individuals holiday and sick pay arrangements, though there is no compulsion to do so.

Aberdeen City said it had employed 4151 workers on zero-hours contracts from 2008 to 2012.

Stirling Council confirmed it had 634 teachers and 542 other workers who work on a supply/zero-hours basis.

Twenty councils in Scotland said they did not use zero-hours contracts, while one - Western Isles - did not provide information.

Ian Brinkley, director of think tank The Work Foundation, said official statistics were likely to be under-recording the use of zero-hours contracts, as they were often referred to in different terms by employers because of the bad publicity they have attracted.

Brinkley said zero-hour contracts could work in some cases: for example, a postgraduate student teaching in addition to their studies or a retired person who does not want to be tied down to a regular job.

But he cautioned: "What we don't know is are you taking these contracts because you choose to or are you taking them because there is nothing else going?"

So-called "elementary jobs", such as labourers and cleaners , account for the biggest proportion of zero-hours contracts at 22%, according to The Work Foundation, while just 2% are held by managers or directors.

Almost one-quarter of zero-hours workers are full-time students. NUS Scotland president Gordon Maloney said while students may value the flexibility of such contracts, this did not make up for the instability they create.

"Employers might think the work comes and goes, but for the employee, the need to pay bills doesn't," he said.

In the NHS, 10 of Scotland's 14 health boards also said they had staff on zero-hours contracts or working in "nurse banks".

Norman Provan, associate director of the Royal College of Nursing Scotland, said "bank" staff were technically on zero-hours contracts, but the vast majority were employees who used the facility to boost their income by working extra shifts.

Other public bodies have some staff on these contracts. National Museums Scotland said that 18 of its 450 staff were on contracts with a "variation in the hours of work available", most of whom were involved in giving workshops.

National Galleries Scotland has seven zero-hours retail staff.

The Scottish Parliament said it did not employ any staff directly on zero hours, but its catering contractor had eight people working under such arrangements, "typically students who help to support evening events held at the Parliament".

Last week, UK Business Secretary Vince Cable said he had asked officials to review the growth of the contracts in both the private and public sectors.

The Scottish Government said while employment policy is reserved to Westminster, it is considering if it can be a legitimate consideration when awarding public-sector contracts.

Figures show that across the UK, around 89,000 people were on zero-hour contracts in 2004. The most recent estimate by the Office for National Statistics, published last week, is that Britain now has 250,000 workers on the contracts.

The Work Foundation's Brinkley pointed out that the current figure is similar to the numbers on zero-hours contracts in 1997 - at the end of the last Tory administration. But he believes the issue is under more scrutiny now as it is symbolic of much bigger changes in the labour market.

"You have got a fearful, concerned workforce, a fall in real wages, lots of insecure employment around," he said. "Zero hours have come to symbolise that uncertain state of affairs in the labour market."

Additional reporting: Scott Dickson